CN1901189A - Plane flip-chip LED integrated chip and producing method - Google Patents

Abstract

The invention discloses a planar flip-chip LED integrated chip with low cost, easy integration and good heat dissipation effect and a manufacturing method. The integrated chip includes several LED bare chips and a silicon substrate, and the LED bare chip includes a substrate (10) and an N-type epitaxial layer (11), a P-type epitaxial layer (12), and the top surface of the silicon substrate is placed on each LED bare chip. There are two separated metal layers (32, 33), and the P-type epitaxial layer (12) and the N-type epitaxial layer (11) are respectively flipped on the metal layers (32, 33) through solder balls (40, 41), There is also an isolation layer I (22, 23) in the bonding area between the metal layer (32, 33) and the silicon substrate, and an isolation layer is provided between the metal layer (32, 33) corresponding to each LED bare chip and the silicon substrate. II (5), a plurality of bare LED chips are connected through metal layers (32, 33) and anode contacts (80) and cathode contacts (81) are drawn out. The method includes the steps of forming an isolation layer, a metal layer, a protection layer and flip-chip LEDs. The invention can be widely used in the LED field.

Description

Planar flip-chip LED integrated chip and manufacturing method

Technical field

The invention relates to a plane flip-chip LED integrated chip and a manufacturing method thereof.

Background technique

Flip-chip technology is one of the most advanced microelectronic packaging technologies today. It is not only a chip interconnection technology, but also an ideal chip bonding technology, which raises the circuit assembly density to a new level. Among all surface mount technologies, flip chip can achieve the smallest and thinnest package. As the size of electronic products shrinks further, the application of flip chip will become more and more extensive. The packaging form in which the bare LED chip is buckled upside down on the silicon substrate is called a flip-chip LED. Traditional flip-chip LEDs use larger power LEDs with higher cost. Due to the larger chip area and concentrated heat source, the heat dissipation effect is not good. At the same time, it is difficult to realize multi-chip integration of this kind of flip-chip LED.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide a flat flip-chip LED integrated chip with low cost, easy integration and good heat dissipation effect and a manufacturing method.

The technical solution adopted by the planar flip-chip LED integrated chip of the present invention is: the planar flip-chip LED integrated chip of the present invention includes several LED bare chips and a silicon substrate, and the LED bare chip includes a substrate and an N-type epitaxial layer, a P-type The epitaxial layer, the top surface of the silicon substrate has two separate deposited metal layers at each of the LED bare chips, and the P-type epitaxial layer and the N-type epitaxial layer are flip-chip welded on the silicon substrate respectively. On the metal layer, there is also a doped isolation layer I in the bonding area between the metal layer and the silicon substrate, and a doped isolation layer I is provided between the metal layer corresponding to each of the LED bare chips and the silicon substrate. There is an isolation layer II, and several LED bare chips are connected through the metal layer to lead out anode contacts and cathode contacts.

Several LED bare chips are connected in parallel or in series or in combination.

The planar flip-chip LED integrated chip of the present invention further includes a protection layer, and the protection layer covers the outer surface of the metal layer.

There is also a heat dissipation layer made of one or more layers of metal on the back of the silicon substrate.

The outer surface of the metal layer is a reflective surface.

The silicon substrate is P-type or N-type, the polarity of the isolation layer I is opposite to that of the silicon substrate, the solder balls are gold ball plugs or copper ball plugs or tin balls, and the metal layer is aluminum or Copper or silicon aluminum alloy.

The technical scheme adopted in the manufacturing method of the plane flip-chip LED integrated chip of the present invention is: it comprises the following steps:

(a) Form isolation layer II: thermally oxidize and grow an oxide layer on the upper surface of the silicon substrate in an oxidation furnace tube, perform photolithography on a photolithography machine using a diffusion photolithography mask, and then use an etching solution containing HF to The oxide layer is etched to remove the oxide layer in the photolithographic pattern part, and the remaining oxide layer forms the isolation layer II;

(b) Form the isolation layer I: thermally diffuse in a high-temperature diffusion furnace to form several isolation layers I whose polarities are opposite to those of the silicon substrate; Implanting ions with opposite properties into the silicon substrate, and then driving into the silicon substrate at high temperature to form several isolation layers I;

(c) Form a metal layer: deposit a metal layer by sputtering or vapor deposition, then use a metal photolithography mask to perform photolithography on a photolithography machine, and then use a wet or dry etching process to etch the metal layer. The remaining metal layer constitutes the metal layer and the anode contact and the cathode contact connected in series or in parallel or in combination of series and parallel;

(d) Forming a protective layer: Deposit a silicon dioxide or silicon nitride protective layer by chemical vapor deposition, then use a protective layer photolithography mask to perform photolithography on a photolithography machine, and then use a HF-containing etching solution to treat the silicon dioxide Etching or dry etching of silicon nitride, so that the protective layer has openings for planting solder balls;

(e) LED bare chip packaging: plant gold ball plugs or copper ball plugs or tin balls in the opening of the protective layer, and then flip several of the LED bare chips (1) on the gold balls by ultrasonic bonding or reflow soldering Bolt or copper ball bolt or tin ball.

The beneficial effects of the present invention are: because several LED bare chips of the flat flip-chip LED integrated chip of the present invention are connected through the metal layer and anode contacts and cathode contacts are drawn out, several LED bare chips are connected in parallel Or connected in series or series-parallel combination, the multiple LED bare chips have a wide distribution area, the luminous effect is better, and the manufacturing cost is lower than that of a power type LED chip using one LED bare chip. The two connected solder balls transfer heat to the metal layer, and transfer heat to the silicon substrate and the heat dissipation layer through the isolation layer 1. The metal layer has a relatively large area, and the heat source Relatively dispersed, good heat dissipation effect, long service life, so the flat flip-chip LED integrated chip of the present invention has good heat dissipation effect, long service life, and is easy to realize multi-chip integration; and because the metal layer of the flat flip-chip LED integrated chip of the present invention The surface is a reflective surface, and the light emitted by the PN junction of the LED bare chip on the bottom surface will be reflected when it encounters the metal layer, and the reflected light will be emitted from the front, so that the light emitted from the bottom surface of the PN junction of the LED bare chip The light is effectively utilized, the waste of light on the bottom surface is reduced, and the luminous efficiency is improved. Therefore, the planar flip-chip LED integrated chip of the present invention has high luminous efficiency and high light intensity from the front; similarly, the planar flip-chip manufactured by the method of the present invention The LED integrated chip has the above-mentioned advantages, and the method has simple process and good product quality.

Description of drawings

Fig. 1 is a schematic diagram of the plane layout structure of Embodiment 1 of the present invention;

Fig. 2 is a schematic circuit diagram of the LED integrated chip shown in Fig. 1;

Fig. 3 is a schematic diagram of the plane layout structure of Embodiment 2 of the present invention;

Fig. 4 is a schematic circuit diagram of the LED integrated chip shown in Fig. 3;

Fig. 5 is a schematic diagram of the plane layout structure of the third embodiment of the present invention;

Fig. 6 is a schematic circuit diagram of the LED integrated chip shown in Fig. 5;

Fig. 7 is a schematic diagram of the plane layout structure of Embodiment 4 of the present invention;

Fig. 8 is a schematic circuit diagram of the LED integrated chip shown in Fig. 7;

Fig. 9 is a schematic diagram of the A-A cross-sectional structure of the planar flip-chip LED integrated chip shown in Fig. 1, Fig. 3, Fig. 5 and Fig. 7

Fig. 10 is a schematic diagram of the B-B cross-sectional structure of the manufacturing method of the planar flip-chip LED integrated chip of the present invention shown in Fig. 1 after step (a) is completed;

Fig. 11 is a schematic diagram of the B-B sectional structure of the manufacturing method of the planar flip-chip LED integrated chip of the present invention shown in Fig. 1 after step (b) is completed;

Fig. 12 is a schematic diagram of the B-B cross-sectional structure of the manufacturing method of the planar flip-chip LED integrated chip of the present invention shown in Fig. 1 after step (c) is completed;

Fig. 13 is a schematic diagram of the B-B cross-sectional structure of the manufacturing method of the planar flip-chip LED integrated chip of the present invention shown in Fig. 1 after step (d) is completed;

Fig. 14 is a schematic diagram of the B-B sectional structure after the manufacturing method step (d') of the planar flip-chip LED integrated chip of the present invention shown in Fig. 1 is completed;

Fig. 15 is a B-B cross-sectional structural diagram after the step (e) of the manufacturing method of the planar flip-chip LED integrated chip of the present invention shown in Fig. 1 is completed.

Detailed ways

Embodiment one:

As shown in Figures 1, 2 and 9, the planar flip-chip LED integrated chip of this embodiment includes nine LED bare chips 1 and a silicon substrate 2, and the LED bare chips 1 include sapphire (Al ₂ O ₃ ) lining Bottom 10 and gallium nitride (GaN) N-type epitaxial layer 11, P-type epitaxial layer 12, certainly, described substrate 10 also can be the substrate of other materials such as silicon carbide (SiC), described silicon substrate 2 is P-type silicon substrate, the top surface of the silicon substrate 2 has two separate deposited metal layers 32, 33 at each of the LED bare chips 1, the metal layers 32, 33 are metal aluminum, of course, it can also be Metal copper or silicon-aluminum alloy is used, and the outer surfaces of the metal layers 32, 33 are reflective surfaces, and the metal layers 32, 33 are not only electrodes, conductors, heat sinks for LEDs, but also light reflectors for bottom light. There is also a heat dissipation layer 7 made of a layer of metal on the back side of the silicon substrate 2. Of course, the heat dissipation layer 7 can also be composed of multiple layers of metal. 40, 41 are flip-chip soldered on the metal layers 32, 33, the solder balls 40, 41 are gold ball plugs, of course, they can also be copper ball plugs or tin balls, and the metal layers 32, 33 and the silicon The bonding area of the substrate 2 also has an N-type isolation layer I22, 23 doped with phosphorus or arsenic, etc. An isolation layer II 5 is arranged between the metal layers 32, 33 and the silicon substrate 2 to prevent leakage or short circuit between the metal layers 32, 33, while the isolation layers I 22, 23 and An electrostatic protection diode is also formed between the silicon substrates 2, which can also play the role of electrostatic protection during the packaging process. At the same time, the isolation layers 1 22, 23 pass the LED bare chip 1 to the metal layer The heat of 32 and 33 is then transferred to the silicon substrate 2, which plays a good role in heat conduction and heat dissipation. Each of the LED bare chips 1 is connected in parallel through the metal layers 32 and 33 to lead out the anode contact 80 and the cathode contact 81, that is, all the LED bare chips 1 between the anode contact 80 and the cathode contact 81 in parallel. The planar flip-chip LED integrated chip of the present invention further includes a protection layer 6 covering the outer surfaces of the metal layers 32 and 33 .

Of course, the silicon substrate 2 can also be an N-type silicon substrate, and at this time, the isolation layers 122, 23 are P-type isolation layers doped with materials such as boron.

As shown in Figures 10 to 14, the manufacturing method of the planar flip-chip LED integrated chip of this embodiment includes the following steps:

(a) Forming the isolation layer II: the upper surface of the silicon substrate 2 is thermally oxidized in an oxidation furnace tube to grow an oxide layer with a thickness of 3000 angstroms, and the thickness of the oxide layer can be controlled in the range of 1000 to 5000 angstroms. On the lithography machine, the diffusion photolithography mask is used for photolithography, and then the oxide layer is etched with HF-containing etching solution to remove the oxide layer in the photolithography pattern part, and the remaining oxide layer constitutes the isolation layer II5. This step The resulting profile is shown in Figure 10;

(b) Forming the isolation layer 1: the isolation layer 1 22, 23 whose polarity is opposite to that of the silicon substrate 2 is formed by thermal diffusion in a high-temperature diffusion furnace, and the isolation layer 1 22, 23 will make the LED two Each electrode is in an isolated state to avoid short circuit and leakage breakdown, and at the same time, the LED bare chip 1 can dissipate heat through the silicon chip. Inject the silicon substrate 2, then drive into the silicon substrate 2 at high temperature to form several isolation layers 122, 23, the final cross-sectional view of this step is as shown in Figure 11;

(c) Forming a metal layer: deposit a metal layer with a thickness of 12000 angstroms by sputtering or evaporation, the thickness of the metal layer can be controlled in the range of 5000 to 40000 angstroms, and then use a metal photolithography mask on the photolithography machine Perform photolithography, and then use the dry etching process commonly used in semiconductor technology to etch the metal layer. Of course, wet etching can also be used to etch the metal layer. The remaining metal layer after etching constitutes the metal layer 32, which is connected in parallel. 33 and the anode contact 80 and the cathode contact 81, the final cross-sectional view of this step is as shown in Figure 12;

(d) Forming a protective layer: depositing a silicon dioxide protective layer with a thickness of 12000 angstroms by chemical vapor deposition, the thickness range of the silicon dioxide protective layer can be controlled at 8000 to 15000 angstroms, and the silicon dioxide protective layer is also It can be replaced by a silicon nitride protective layer, and then photolithography is carried out on a photolithography machine using a protective layer photolithography mask, and then silicon dioxide is etched with an etching solution containing HF or silicon nitride is etched by a dry method, so that The protective layer has openings for planting solder balls, and the final cross-sectional view of this step is shown in Figure 13;

(d') Form heat dissipation layer: deposit a layer of aluminum metal layer or a multilayer metal layer containing titanium, nickel, silver and other materials on the back side of the silicon substrate 2 by metal sputtering or vapor deposition to form the The heat dissipation layer 7, the cross-sectional view formed at the end of this step is shown in Figure 14;

(e) LED bare chip packaging and flip-chip: plant gold ball plugs in the openings of the protective layer, and then flip-chip each of the LED bare chips 1 on the gold ball plugs by ultrasonic bonding. Of course, the gold ball plugs can also be made of copper. For ball plugs or solder balls, when solder balls are used, it is necessary to flip-chip several LED bare chips 1 on the solder balls by reflow soldering. The final cross-sectional view of this step is shown in FIG. 15 .

Embodiment two:

As shown in Fig. 3, Fig. 4 and Fig. 9, the difference between this embodiment and Embodiment 1 lies in: the connection mode between the LED bare chips 1 through the metal layers 32, 33—this embodiment The LED bare chips 1 are connected in series, that is, all the LED bare chips 1 between the anode contact 80 and the cathode contact 81 are connected in series.

The remaining features of this embodiment are the same as those of Embodiment 1.

Embodiment three:

As shown in Fig. 5, Fig. 6 and Fig. 9, the difference between this embodiment and Embodiment 1 lies in: the connection mode between the LED bare chips 1 through the metal layers 32, 33—this embodiment Each of the LED bare chips 1 is connected in series every three groups, and then the three groups are connected in parallel.

The remaining features of this embodiment are the same as those of Embodiment 1.

Embodiment four:

As shown in Fig. 7, Fig. 8, and Fig. 9, the difference between this embodiment and Embodiment 1 lies in: the connection mode between the LED bare chips 1 through the metal layers 32, 33—this embodiment Each of the LED bare chips 1 is connected in parallel every three to form a group, and then the three groups are connected in series.

The remaining features of this embodiment are the same as those of Embodiment 1.

The number of LED bare chips 1 described in the planar flip-chip LED integrated chip of the present invention is not limited to nine, and the embodiment is only for illustration.

The present invention integrates several LED bare chips 1 on one silicon substrate 2, which has good heat dissipation effect, long service life, improved luminous efficiency, low cost and easy realization of multi-chip integration.

The invention can be widely used in the LED field.

Claims (8)

1. A planar flip-chip LED integrated chip, comprising several LED bare chips (1) and a silicon substrate (2), the LED bare chip (1) including a substrate (10) and an N-type epitaxial layer (11) , P-type epitaxial layer (12), the top surface of the silicon substrate (2) has two separate deposited metal layers (32, 33) at each of the LED bare chips (1), the P-type epitaxial layer The layer (12) and the N-type epitaxial layer (11) are respectively flip-chip welded on the metal layers (32, 33) through solder balls (40, 41), and it is characterized in that: the metal layers (32, 33 ) and the silicon substrate (2) respectively have a doped isolation layer I (22, 23), the metal layers (32, 33) corresponding to each of the LED bare chips (1) and An isolation layer II (5) is provided between the silicon substrates (2), and several LED bare chips (1) are connected through the metal layers (32, 33) and anode contacts (80) are drawn out and cathode contact (81). 2. The planar flip-chip LED integrated chip according to claim 1, characterized in that: several LED bare chips (1) are connected in parallel or in series or in combination. 3. The planar flip-chip LED integrated chip according to claim 1, characterized in that it further comprises a protective layer (6), and the protective layer (6) covers the outer surfaces of the metal layers (32, 33). 4. The planar flip-chip LED integrated chip according to claim 1, 2 or 3, characterized in that there is a heat dissipation layer (7) made of one or more layers of metal on the back of the silicon substrate (2). 5. The planar flip-chip LED integrated chip according to claim 1, 2 or 3, characterized in that: the outer surface of the metal layer (32, 33) is a reflective surface. 6. The planar flip-chip LED integrated chip according to claim 1, 2 or 3, characterized in that: the silicon substrate (2) is P-type or N-type, and the isolation layers I (22, 23) and The polarity of the silicon substrate (2) is opposite, the solder balls (40, 41) are gold ball plugs or copper ball plugs or tin balls, and the metal layers (32, 33) are aluminum or copper or silicon aluminum alloy . 7. A method for manufacturing the planar flip-chip LED integrated chip according to claim 1, characterized in that it comprises the following steps: (a) Form isolation layer II: thermally oxidize and grow an oxide layer on the upper surface of the silicon substrate (2) in an oxidation furnace tube, perform photolithography on a photolithography machine using a diffusion photolithography mask, and then use HF-containing The etching solution etches the oxide layer to remove the oxide layer in the photolithographic pattern, and the remaining oxide layer forms the isolation layer II (5); (b) Form the isolation layer I: heat diffusion in a high-temperature diffusion furnace to form several isolation layers I (22, 23) whose polarity is opposite to that of the silicon substrate (2), or, use ion implantation Implanting ions with a polarity opposite to that of the silicon substrate (2) into the silicon substrate (2), and driving into the silicon substrate (2) at high temperature to form several isolation layers I (22 ,twenty three); (c) Form a metal layer: deposit a metal layer by sputtering or vapor deposition, then use a metal photolithography mask to perform photolithography on a photolithography machine, and then use a wet or dry etching process to etch the metal layer. The remaining metal layers constitute the metal layers (32, 33) connected in series or in parallel or combined series and parallel, and the anode contact (80) and cathode contact (81); (d) Forming a protective layer: Deposit a silicon dioxide or silicon nitride protective layer by chemical vapor deposition, then use a protective layer photolithography mask to perform photolithography on a photolithography machine, and then use a HF-containing etching solution to treat the silicon dioxide Etching or dry etching of silicon nitride, so that the protective layer has openings for planting solder balls; (e) LED bare chip packaging: plant gold ball plugs or copper ball plugs or tin balls in the opening of the protective layer, and then flip several of the LED bare chips (1) on the gold balls by ultrasonic bonding or reflow soldering Bolt or copper ball bolt or tin ball. 8. The method of planar flip-chip LED integrated chip according to claim 7, characterized in that: between step (d) and step (e), the following steps are further included: (d') Forming a heat dissipation layer: depositing a layer of aluminum metal layer or a multi-layer metal layer containing titanium, nickel, silver and other materials on the back side of the silicon substrate (2) by metal sputtering or vapor deposition to form The heat dissipation layer (7).

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